WASHINGTON  A farm bill that would continue billions of dollars in government payments to farmers was approved by a Senate committee Thursday as critics vowed to try and reduce those subsidies.

The Senate Agriculture Committee unanimously approved the five-year bill, which would provide more than $280 billion for agriculture and nutrition programs and leave in place most subsidies to producers of major U.S. crops.

Critics say the bill devotes too much money to wealthy farmers and should divert those dollars to conservation programs that protect the land, food aid to the poor or reducing the federal deficit.

"This committee could do much better on behalf of not just farmers, but all taxpayers," said Sen. Richard Lugar, R-Ind., a member and former chairman of the panel who said he plans to challenge the bill on the Senate floor. "Each passing year the policies seem ever more misguided."

The legislation does attempt to limit subsidies with a provision that would eventually ban government payments to "non-farmers" whose income averages more than $750,000 a year. The bill defines farmers as those who make more than two-thirds of their income from agriculture.

There would be no income-based limits on what a person defined as a farmer can collect from the government.

The committee's unwillingness to substantially reduce subsidies was highlighted when Lugar offered an amendment to cut $1.7 billion from direct payments, subsidies that are often criticized because they are not based on current crop production or prices. The amendment would have shifted that money to nutrition programs, including food stamps and emergency food assistance.

Members of the agriculture panel praised Lugar's amendment, then swiftly voted against it, 17-4. Supporting the amendment were Lugar and Democratic Sens. Bob Casey of Pennsylvania and Sherrod Brown of Ohio. Senate Republican Leader Mitch McConnell of Kentucky, who did not attend the meeting, originally voted against it by proxy but later changed his vote.

North Dakota Sen. Kent Conrad, a Democrat who negotiated the bill with Senate Agriculture Committee Chairman Tom Harkin, D-Iowa, later said that he hoped that any additional savings achieved from the bill would be diverted to Lugar's nutrition proposal.

The legislation is expected to face obstacles once it reaches the Senate floor. Republican Sen. Charles Grassley of Iowa, a committee member who called the payment limits "window dressing," has said he and Sen. Byron Dorgan, D-N.D., will offer an amendment to cap overall payments at $250,000 a year. They are currently capped at $360,000.

Lugar and Sen. Frank Lautenberg, D-N.J., have said they will offer an alternative bill that would eliminate direct payments completely and replace them with crop insurance for all farmers.

Committee members also expressed concern about a new subsidy program that would give farmers an option to collect payments when crop revenue is low compared to a statewide average, as opposed to current subsidies that kick in when prices are low. This type of payment program has been proposed by the Department of Agriculture and corn growers, who have seen record-high prices in recent years.

Committee members expressed concerns that the provision would be too complicated to carry out and would harm the crop insurance industry. The panel adopted an amendment by Sen. Pat Roberts, R-Kansas, that would tweak the provision in an effort to mollify some of the criticism.

The bill, which also boosts money for conservation programs, energy programs and loan support for several crops, could also attract a controversial immigration amendment. Senate Majority Leader Harry Reid, D-Nev., said earlier this week that senators may try to attach legislation that would give legal status to some temporary migrant farm workers.

The Senate Finance Committee passed farm legislation earlier this month that would add extra money to the agriculture committee bill, including $5 billion in weather-related agricultural disaster aid. Together, the two bills total around $288 billion.